For satisfactory results in gas tungsten arc welding, (GTAW), it is necessary, and required, that certain volumes of inert gas such as argon or helium be maintained as an atmosphere for shielding both sides of each G.T.A. weld while it is being made. Too much or too little shielding gas, within comparatively close limits, involves a rejection for a defectiveness which entails a complete rewelding and rechecking sequence.
Moreover, although conventional equipment presently employed is certifiable generally, adjustability and pressure variations occur in the supply of shielding gas and there may be no certainty as to the cause why defective welds occur. Some causes may be direct and others indirect.
The pressure and flow in conventional pressure controlled manifold supply systems constantly varies with an irregular number of welds being shielded at a given time. The flow volume through a service stage regulator which has a low pressure output can drop enough to affect the welds adversely, while too much flow also causes problems as well as wastes expensive gas.
Furthermore, under present practice, the gas supply flow is variable depending upon the number of welds being made at a given time in manufacture or repair operations at widely spaced sites, and the flow capability in a manifold supply system varies continuously along with the stored pressure supply volume of the tanks and the distance of flow from the manifold regulator and frictional flow through conduits, particularly flexing hoses of different lengths.
More often than not, an individual welder is logically and primarily blamed for a bad weld, for any one of several reasons, some of which may be beyond his control, and he in turn blames his equipment, unless several welds by different welders happen to be rejected. Then the shielding gas supply equipment is blamed even though it may only have been temporarily overloaded, but, by this time many poor welds are involved that require correction at substantial cost and production delays.
To avoid this, to save time, improve results and pin point difficulties and responsibility, both the flow rate and pressure of the shielding gas supply must be closely controlled knowingly, and mobile welding equipment perfected for constancy and uniformity of welds regardless of distance of use from the source of pressurized gas supply, not only for the benefit of the performance record of the welder, the company and the equipment, but particularly for the avoidance of reworking rejects and the waste of gas that occurs either way.